BackgroundThe incidence of microbial resistance is increasing, and new rescue regimens are needed in order to treat Helicobacter pylori (H. pylori) infection. To evaluate the efficacy, safety, and tolerability of levofloxacin based quadruple therapies in the eradication of H. pylori.MethodsIn a randomized, double-blind clinical trial, 220 patients with dyspepsia and H. pylori infection were randomly assigned to receive either bismuth subcitrate 240 mg, pantoprazole 20 mg, amoxicillin 1000 mg twice a day, and levofloxacin 500 mg daily for seven days (BPAL-7), or ten days (BPAL-10). The eradication of H. pylori was evaluated two months after the end of treatment, and adverse drug reactions (ADRs) were assessed during the intervention.ResultsAccording to intention-to-treat and per-protocol, the eradication rate was significantly lower in the BPAL-7 regimen 49.1% (95% CI: 39.3–57.8) and 47.6% (95% CI: 39.7–58.4), respectively compared to the BPAL- 10 regimen 62.7% (95% CI: 53.6–72.8) and 62.4% (95% CI: 55.1–72.8), respectively. The incidence of ADRs was not statistically significant between BPAL-7 (33.6%) and BPAL-10 (36.7%) groups.ConclusionAlthough the ADRs were negligible in both groups, these regimens could not be an ideal alternative therapy for H. pylori because of low eradication rates compared to standard regimens.Trial registration: The study reviewed and approved by the Iranian Registry of Clinical Trials (IRCT201406141155N19). This trial was retrospectively registered on July 10, 2015.